PROJECT SUMMARY/ABSTRACT Craniofacial dysmorphologies are among the most common features of developmental disorders, and often have profound and enduring effects on quality of life. Such are a common feature of ciliopathic syndromes, a class of phenotypically variable developmental disorders caused by defects of the primary cilium. However, the developmental causes of ciliopathic craniofacial anomalies are not well characterized. Ciliopathy patients with mutations in a poorly characterized gene, Wdpcp, often present with craniofacial dysmorphologies. However, the role of Wdpcp in craniofacial development has never been directly studied. Here, I plan to use a Wdpcp loss of function mouse line to characterize the embryological progression of the observed dysmorphologies. I will utilize mouse genetics to probe for genetic interactions that may modulate phenotypes in human patients. Lastly, I will interrogate the mechanism of pathogenesis of diseases mutations through cell biology and proteomic experiments. Successful completion of these aims will provide valuable insights into the underlying molecular, cellular, and anatomical causes of craniofacial dysmorphologies observed in Wdpcp ciliopathy patients.